The first single released from the album was "The Rain (Supa Dupa Fly)".[7] As part of the promotional drive for her album, Elliott took part of the 1998 Lilith Fair tour; she became the first female rapper to perform at the event.[8] She also joined rapper Jay-Z's Rock the Mic tour.[8]

Supa Dupa Fly brings together elements of hip hop, dance, R&B, electronic music, and soul.[9][10] Music critic Garry Mulholland described Timbaland's production as "eschewing samples for a bump 'n' grind electronica, strongly influenced by the digital rhythms of dancehall reggae, but rounder, fuller, fatter".[11]AllMusic described it as consisting of “lean, digital grooves [...] packed with unpredictable arrangements and stuttering rhythms that often resemble slowed-down drum'n'bass breakbeats."[9] Elliott’s raps were described as “full of hilariously surreal free associations that fit the off-kilter sensibility of the music to a tee.”[9] According to author Mickey Hess, the album's lyrical content "reveals Elliott's complex, creative, and challenging discussion about womanhood; her demand for respect, respect for her personal voice and her desire for fulfilling intimacy with lovers and friends".[12] The album's opening track, "Busta's Intro", features rapper Busta Rhymes as a town crier warning of a "historical event about to unfold".[12] "The Rain (Supa Dupa Fly)" contains a sample of Ann Peebles' 1973 song "I Can't Stand the Rain".[13] "Pass da Blunt" is partly based on the song "Pass the Dutchie" by Musical Youth.

Upon its release, Supa Dupa Fly received acclaim among music critics. Writers lauded record producer Timbaland's production as unique and revolutionary. AllMusic called the album a “boundary-shattering postmodern masterpiece” whose “futuristic, nearly experimental style became the de facto sound of urban radio at the close of the millennium.”[9] Elliott's rapping, singing and songwriting also received much acclaim. The 2004 edition of The Rolling Stone Album Guide rated the album five out of five stars, noting that the avant-garde sound of the album "made Elliott and Timbaland the hottest writer/producer team around".[20] Mulholland called the album a "key prophecy of the dominant 21st century black pop", noting Elliott's ability to "avoid the whole east vs. west, playas vs. gangstas mess." He described Elliott's style as "everything the hip hop doctor ordered; a woman who could flip between aggression and romance, sex and nonsense, materialism and imagination, without batting one outrageously spidery eyelash".[11]